Analysis and Characterization of an Unclassified RFI Affecting
Ionospheric Amplitude Scintillation Index over the Mediterranean Area
Abstract
Radio Frequency (RF) signals transmitted by Global Navigation Satellite
Systems (GNSS) are exploited as signals of opportunity in many
scientific activities, ranging from sensing waterways and humidity of
the terrain to the monitoring of the ionosphere. The latter can be
pursued by processing the GNSS signals through dedicated ground-based
monitoring equipment, such as the GNSS Ionospheric Scintillation and
Total Electron Content Monitoring (GISTM) receivers. Nonetheless, GNSS
signals are susceptible to intentional or unintentional RF interferences
(RFIs), which may alter the calculation of the scintillation indices,
thus compromising the quality of the scientific data and the reliability
of the derived space weather monitoring products. Upon the observation
of anomalous scintillation indices computed by a GISTM receiver in the
Mediterranean area, the study presents the results of the analysis and
characterization of a deliberate, unclassified interferer acting on the
L1/E1 GNSS signal bands, observed and captured through an experimental,
software defined radio setup. The paper also highlights the adverse
impacts of the interferer on the amplitude scintillation indices
employed in scientific investigations, and presents a methodology to
discriminate among regular and corrupted scintillation data. To support
further investigations, a dataset of baseband signals samples affected
by the RFI is available at IEEE DataPort.